1. Field of the Invention
The present invention relates to a test method and a test apparatus for performing a withstand voltage test or an insulation resistance test between a live electrical section electrically connected to a solar cell and an outer housing conductor section of the solar cell in a photovoltaic solar panel. The present invention also relates to a manufacturing method for manufacturing the solar panel, an inspection method and an inspection apparatus for a solar panel generating system, an insulation resistance measuring apparatus, and a withstand voltage tester for use in the test apparatus, and the inspection apparatus.
2. Description of the Related Art
As people become more ecology conscious, public expectations for solar panels, which use clean energy, increase. Solar panel integrated building material modules, into which a solar panel and a building material are integrated, draw particular attention. xe2x80x9cIntegrated roof solar panel modulesxe2x80x9d and xe2x80x9cintegrated wall solar panel modulesxe2x80x9d have been actively developed. These modules are increasingly used as roofs and walls of homes or buildings, year by year.
Referring to rough sectional views shown in FIG. 2 and FIG. 3, these known integrated solar panel modules employ a steel plate on the bottom side thereof for reinforcement or a metal frame surrounding the panel for easy installation. A plurality of these panel modules are installed, thereby forming an array of solar panels. A plurality of arrays are connected at a junction box to collect electricity. Using an inverter, generated direct current power is converted into an alternating current power to be used across a load or to be fed back to a power line.
When the solar panel modules, not limited to the integrated solar panel modules, are manufactured, at least one of an insulation resistance test and a withstand voltage test is performed to test insulation performance and withstand voltage performance between a conductor section (a live electrical section) connected to a solar cell and a conductor section of an outer housing. Thereafter, a voltage difference takes place between the solar cell and the outer housing in the solar panel module. To quickly reduce the voltage difference, the conductor section of the outer housing is shorted.
If an attempt is made to short the live electrical section electrically connected to the solar cell, a residual charge occurs again subsequent to the removal of a shorting wire. A discharge could occur between the live electrical section electrically connected to the solar cell and the conductor section of the outer housing, thereby occasionally breaking down the solar cell itself. It is believed that a voltage difference occurs again due to the generation of a charge attributed to dielectric polarization in a material filling the solar cell. The method of shorting the live electrical section momentarily reduces the voltage difference therebetween. After the shorting circuit is opened, a residual charge occurs again, thereby causing a voltage difference therebetween.
During a maintenance service of a solar panel generating system, an insulation resistance measurement may be performed on a solar array one by one. When one solar panel array is measured after the measurement of another, a residual charge occurs in the solar panel array or in the solar panel module as a result of the preceding measurement, and a precise measurement of insulation resistance becomes difficult. As a preventive step for resolving this problem, a shorting wire may be connected between the live electrical section connected to the solar cell and a terminal connected to the conductor section of the outer housing (for example, a ground terminal) to lower the potential. During this operation, however, an arc may develop as a result of discharging. After removal of the shorting wire, a residual charge may occur again.
When an insulation resistance measuring apparatus having an automatic discharging function is employed, an accumulated charge is drained if a measuring probe is left connected. A subsequent removal of the probe can cause a voltage difference again.
Another method is simply waiting until the charge is self-discharged. However, this takes a substantially long period of time.
In view of the above problems, it is an object of the present invention to provide a test method and a test apparatus for testing a solar panel in a manner such that a residual charge from an insulation resistance test or a withstand voltage test is reliably removed within a short period of time, a manufacturing method for manufacturing the solar panel, an inspection method and an inspection apparatus for a solar panel generating system, and an insulation resistance measuring apparatus and a withstand voltage tester.
A test method of the present invention for testing a solar panel including, at least, both a solar cell and an outer housing, includes a step of performing one of a withstand voltage test and an insulation resistance test between a live electrical section electrically connected to the solar cell and a conductor section of the outer housing, and a step of applying a voltage between the live electrical section and the conductor section after the one of the withstand voltage test and the insulation resistance test has been performed.
An inspection method of the present invention for inspecting a solar panel generating system including a solar panel including, at least, both a solar cell and an outer housing, includes a step of performing one of a withstand voltage test and an insulation resistance test between a live electrical section electrically connected to the solar cell and a conductor section of the outer housing, and a step of applying a voltage between the live electrical section and the conductor section after the one of the withstand voltage test and the insulation resistance test has been performed.
A test apparatus of the present invention for testing a solar panel including, at least, both a solar cell and an outer housing, includes a unit for performing one of a withstand voltage test and an insulation resistance test between a live electrical section electrically connected to the solar cell and a conductor section of the outer housing, and a unit for applying a voltage between the live electrical section and the conductor section after the one of the withstand voltage test and the insulation resistance test has been performed.
An inspection apparatus of the present invention for inspecting a solar panel generating system including a solar panel including, at least, both a solar cell and an outer housing, includes a unit for performing one of a withstand voltage test and an insulation resistance test between a live electrical section electrically connected to the solar cell and a conductor section of the outer housing, and a unit for applying a voltage between the live electrical section and the conductor section after the one of the withstand voltage test and the insulation resistance test has been performed.
A manufacturing method of the present invention for manufacturing a solar panel including, at least, a solar cell, a surface protective covering member for encapsulating the solar cell, and an outer housing, includes a step of encapsulating the solar cell with the surface protective covering member, a step of performing one of a withstand voltage test and an insulation resistance test between a live electrical section electrically connected to the solar cell and a conductor section of the outer housing, and a step of applying a voltage between the live electrical section and the conductor section after the one of the withstand voltage test and the insulation resistance test has been performed.
The voltage applied between the live electrical section and the conductor section is preferably an alternating current voltage. The outer housing is preferably a bottom surface reinforcement member for reinforcing the bottom surface of the solar panel. The solar panel preferably includes a metal plate. The metal plate is preferably a stainless steel sheet. The voltage applied between the live electrical section and the conductor section of the outer housing is preferably fed from a utility power line.
An insulation resistance measuring apparatus of the present invention includes a unit of applying a voltage across test terminals subsequent to an insulation resistance test.
A withstand voltage tester of the present invention includes a unit of applying a voltage across test terminals subsequent to a withstand voltage test.
During the manufacturing and testing of a solar panel, or during the inspection of a solar panel generating system, a withstand voltage test or an insulation resistance test is performed across test terminals between a live electrical section connected to a solar cell and an outer housing conductor in a solar panel using a withstand voltage tester and an insulation resistance measuring apparatus. A voltage difference occurs between the live electrical section and the conductor section of the outer housing, owing to a residual charge from these tests. The residual charge cannot be efficiently removed by techniques of shorting the live electrical section to the conductor section of the outer housing or of an automatic discharging function of a tester. The use of a self-discharge-phenomenon takes a long time before the residual charge is substantially reduced. In accordance with the present invention, a voltage is applied between the live electrical section and the conductor of the outer housing subsequent to the withstand voltage test or the insulation resistance test. The residual charge is thus quickly and effectively reduced.
Further objects, features, and advantages of the present invention will be apparent from the following description of the preferred embodiments with reference to the attached drawings.